Alfred bogiscii



UNITE STATES ATENT ALFRED BOGISCII, Oh FEUERBACII, GERMANY, ASSIGNOR TO THE FIRM OF J. IIAUFF, OF SAME PLACE.

Pi-IOTOGRAPi-iifi DEVELOPER AND PROCES OF DEVELOPING.

SPECIFICATION forming part Of Letters Patent N0. 619,066, dated. February 7, 1899;

Application filed December 29, 1897. Serial No. 664,434. (No specimens.)

To alt whom it may concern.-

Be it known that I, ALFRED BOGISCH, doctor of philosophy, a citizen of the German Empi're, residing at Feuerbach, near Stuttgart, in the Kingdom of VViirtcmberg and Empire of Germany, have invented certain new and useful Improvements in Processes of Developing Photographic Images, of which the following is a specification.

The paraphenylendiamins possessed heretofore only a certain theoretical value as developers for the photographic image on sensitized films, inasmuch as they represented a type of developers whose property of development is due to the presence of two amido groups which are laced in the para positions to each other. 0 practical application was given to these diamins, however, for the reason that even by the use of caustic alkalies for developing the image on the sensitive film they were entirely insuiiicient for practical purposes, and, furthermore, because theyproduced greenish veils on the film. 'lhe paraphenylendiamins became only then of practical importance when they were converted into their alkyl derivatives, as described in German Patent No. 69,582, as those derivatives produced the photographic image clearly without greenish veils and with very fine grain even by the use of the suliito of an alkali. For producing, however, the intensity necessary for ordinary copying purposes the alkylized paraphonylendiamius require, notwithstanding thcir considerable initial rapidity of development by which they are cl1aracterizcd, a considerably-cxtcndcd time for developing the image. 'lhcir solutions do not possess the required permanency and a!- feot slightly-sensitive fingers. An entirely different result is obtainedwhcn tho carboxylized alkyl derivatives of the paraphenylen- (liamins (glycins) are used, as they develop the photographic image quickly with alkali sulfites without any coloration of the gelatin film and with the same fine grain as the alkylized paraphcnylondiamins, but with a greater density of the silver precipitate. 'lho alkaline solutions of these glycins ol' the al; kylized paraphenylondiamins can be prepared in a very conccntratcijl form and have a permanency which is not possessed by any one oi the developers heretofore employed.

The glycins ot' the alkylized paraphcnylcndiamins have the following advantages:

First. Iermanencyof thcirsolutions, rapid 55 development of the photographic image on the film oven with solutions containing alkali sulfitcs, together with a full density of the high lights, and a high degree of sensitiveness againt potassium bromid as a rotarder 6d of development.

Second. The negatives do not show the slightest coloration of the film even when caustic alkali or alkali carbonate is used. The films have a very fine grain similar to that of moist collodion plates.

The glycins of the aikylized paraphenylcn- :liamins have the following constitutional formula:

1NR,R2 4 Nll. 0,11,... coon. (Rzalkyl).

So far the best results have been attained by the dialkylized glycins of tho paraphenylendiamin, paratoluylendiamin, paraxylylendiamin, alpha-beta naphthylendiamin, and alpha-alpha naphthylondiamin.

The following proportions are preferably used for the developing solution: one gram dimoth yl-para-amidophenylglycin,five grams sodium sulfite, five grams potassium carbonate, and one hundred grams water.

Having thus described my invention, I claim as new and desire to secure by Letters 8 latcnt- 5 1. The process herein described of developing the photographic image on sensitized plates, which consists in subjecting the sensitizod plates to the action of a solution of the glycin of an alkylizcd paraphenylendiamin, substantially as setforth.

:3. A photographic developer consisting of an alkaline solution of the glycin of an all ylized paraphcnylcndiamin, substantially as set forth. 95

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

ALFRED BOGISOII.

W it i 1 esscs FRDK. IIAUFF, WM. HAHN. 

